Spray head



July 7, 1936. w TRACY 2,046,592

SPRAY HEAD Filed April l0, 1931 lll/)111 lll/vI/llllllllllIl/IIIZN ggg I Patented July 7, H93@ SPRAY HEAD Robert W. Tracy, Toledo', hio, assigner to The De Vilbiss Company, Toledo, hio, a corporation of Ohio Application April 10, 1931, Serial No. 529,016

' 7 Claims.

'I'hs invention relates to spray coating apparatus, and particularly to devices adapted for spraying interior surfaces of pipes, cans and other objects of a cylindrical nature.

The object of the invention is the provision of a simple and eicient device of the character described, which is operable to thoroughly mix the air and material being sprayed, and to eieot the discharge in such manner as to effectively reach all portions of the interior surface of the article being treated as the nozzle is passed therein.

Another object of the invention is the provision of an attachment for spray-guns of the character described, which may be easily and quickly substituted for the spray head used in connection with such guns for coating at surfaces and adapt it for the spraying of the inner surfaces of com paratively small cylindrical articles. The invention is fully described in the following specication and whilein its broader aspect it is capable of embodiment in various forms, two embodiments thereof are illustrated'in the accompanying drawing, in which- Figure 1 is a side elevation of a spray head embodying the invention with parts in central longitudinal section, with parts broken away, and with the nozzle projecting into a cylindrical object which is fragmentarily shown. Fig. 2 is a'sectlon on the line 2-2 in Fig. l. Fig. 3 is a section on the line 3--3 in Fig. l; Fig. 4 is a slightly enlarged sectional detail of the forward end portion of the nozzle with a part in full, and Fig.v 5 is a view similar to Fig. 4 with the inner member oi the nozzle slightly modied.

Referring to the drawing, I designates the portion of a spray-gun body to which the sprayhead is attached and which is provided at its forward end with an enlargement 2, and has the centrally disposed longitudinally extending bore 3 in communication. throughs nipple 4 and suitable connection (not shown), with a source of supply for the material to be sprayed. AThe enlargement 2 is also provided with a passage 5 adapted to have communication with a controlled source of air pressure. supply, as well understood in the art. A spray-gun having a body member of this character and equipped with a spray head for discharging either a cylindrical or fan type t0 of spray stream is illustrated in U. S. Letters Patent. No. 1,613,588, dated January a, 1927.

In the equipment of the invention shown in Figs. 1 to 4. t designates the inner or material discharge nozzle and 'l the outer nozzle which 'H cooperates with the inner nozzle to control the discharge of both the air and material in spray form.

The outer nozzle which for convenience may be termed the air nozzle, has its throat large at its inner end and conically restricted at its for- 5 ward end to its discharge opening, and is carried at the forward end of an extension tube 8, the rear end of which is engaged within and firmly held by an annular member 9. A union-nut I@ is threaded on the body enlargement 2 and has 10 an internal ange engaging a cooperating ange on the member 9 to hold it to the body. The nozzle I may be threaded in the tube or otherwise secured thereto. The length of the tube depends on the character of work to be perl5 formed, and if the work is short the nozzle can be attached directly to the enlargement 2 in the same manner that the member 9 is attached, or in any other suitable way. i

The inner nozzle S has a portion I I fitted in 20 the front of the nozzle 'I and provided with one or `more spiral grooves I2, which cooperate with the nozzle l to form spiral air passages from one side to the other ofV said portion. The nozzle 6 has a tongue-like part I3 projecting forwardly from the 25 spirally grooved portion il and through the discharge orifice of the nozzle 'I in spaced concentric relation to the nozzle and orifice walls. The surface o the part I3 is preferably, but not necessarily. Provided with a succession of spaced annu- 30 lar ribs I6 to a point near the outer nozzlel orice and has an annular rib or enlargement I5 at its outer end without the oridce which obstructs the forward discharge of spray from the nozzle and causesit to be deflected annularly in disk form, as 35 indicated at I6, against the'interior wall of an 'article A into which the gun nozzle may be projected. The portion of the tongue-part I3, be tween the outermost rib I d and the rib or knob I5, cooperates with the end of the outer nozzle I 40 to form an annular dlschargeoriice Il, which is longitudinally curved or shaped to change the course of a discharging iiuid stream from a longitudinal-or axial'direction to ne at substantially `a right-angle thereto. Even if the spray direet-v 45 ing rib I5 is eliminated, leaving the outer end of r the inner nozzle member smooth and rounded. as shown at I5 in Figure 6, there is still a marked tendency for the discharging stream to follow the continuous curve of the inside surface of the lip at the extremity of the outer nozzle, especially when the' stream follows a spiral course through the nozzle, causing acentrifugal action. The use of the rib I5. however, connes the spray into a somewhat narrow stream.

'Ihe material to be sprayed is discharged from the throat I 8 of the nozzle 6 into the mixing space I9 surrounding the tongue-part I3 through lateral openings and is there picked up and thoroughly mixed 'by the discharging airwhich is given a whirling action by reason of its passage through the spiral passages I2. The nozzle 6 is provided at its rear end with a threaded stud part 2I which may be threaded directly into the bore 3 of the body, if the spray` head is to be short-coupled, or it may be projected forwardly from said body to suit the extent of projection of the nozzle 'I by an interposed tubular throat structure, as shown. In the present instance .thisthroat structure is shown as comprising an inner part 22 that is threaded into the throat-bore 3 of the body, a tubular part 23 threaded onto the forward end' of the part 22, and a union part 24 connecting the part 23 to the nozzle 6.

'I'he throat structure 22, 23, 24 for the nozzle 6 cooperates with the body enlargement 2 and with the extension means for the outer nozzle 1 to provide an annularair passage 25 between the air inlet passage 5 and the spiral passages I 2. In order to cause the air to be uniformlydistributed around the passage 25, said passage is provided at itsfinner end with a choke or damming part 26 that is carried by said throat structure. 21 indicates the customary control valve for a material discharge and which has its forward end adapted to seat inthe forward conically restricted end portion of the throat passage I8 to close such passage.

- Itis apparent with this form of spray head that a discharge of air under pressure through the spiral passages I2 into the mixing chamber I9 will cause the air to have a rapid whirling I movement in such chamber and to continue suchv whirling action as it is ldischarged from the orilice I'I. As the material to be sprayed enters the chamber I9, which may be either by the suction action created by the discharging air, or by pressure exerted on the material, or by both, the material is picked up by the whirling air and effectively mixed therewith and then discharged from the annular orifice II and deflected by the rib I5 to form a spray which discharges laterally from the nozzle in all radial directions around the same, so as to coat the interior wall of a cylindrical object in which the nozzle may be projected. The lateral discharge of the material from the nozzle is eected both by the defiecting action of the rib I5 and by centrifugal action due tothe whirlingof the spray. The purpose of the sucy cessive ribs I4 on the inner nozzle tongue I3 is to assist in the breaking up and i'lnally commingling of the material with the-air.

It is apparent that I have provided a simple and eilicient spray head for spray-guns of the air-brush type and that the primary feature vof ,or form of the parts, as it is capable of numerous modifications and changes without departing` from the spirit of the claims.

Having thus described my invention, ,what I claim as new and desire to secure by United States tion to the air in its passage through said space before passing said material discharge.

2. Ina spray head of the class described, inner and outer nozzles cooperating to form an air space in surrounding relation to the inner nozzle,

which space, at its inner end, is adapted to have communication with a source of air pressure supply and at its outer end communication with the discharge orifice of the outer nozzle, said inner nozzle having a lateral material discharge into said space, and a tongue-portion cooperating with the outer nozzle to form an annular discharge orice, discharging at right angles to the longitudinal axis of the nozzle said inner nozzle having one or more bathing members within said space in advance of its point of discharge therein, and means within said space at the rear of said point of material discharge forming spiral passages for the air entering the space.

3-. In a spray head of the clam described, an outer air discharge nozzle, an inner material discharge nozzle having a tongue projecting through the discharge orifice of the outer nozzle and cooperating therewith to form a restricted annular discharge orice, the outer end of which directs the discharge therefrom in a lateral direction with respect to the nozzle axis, said nozzles cooperating to form an air space therebetween in communication with said discharge oriiice and with a source of air pressure supply, said inner 'nozzle having its material discharge into said space,- and means for imparting a` whirling action to `the .air` in its discharge through said space.

4. In a. spray head of the class described, an outer air nozzle having a discharge orifice, an inner material discharge nozzle having a tongue projecting through said discharge orice in concentric spaced relation thereto, and having a lateral spray deflecting surface without said oriiie,

. said nozzles formingan air space therebetween adapted to have communication with a source of air pressure supply, and the inner nozzle having its material discharge laterally into said Space.

5. In a spray head ot the class described, 'an outer nozzle having a discharge orice with the inner surface of its lip portion gradually curving outwardly from a line concentric to the nozzle axis, an inner nozzle, means to discharge material laterally fromV said inner nozzle rearwardly of the discharge end of said outer nozzle and means for imparting a whirling action to the air and material discharging fromsaid nozzles through said outer nozzle orifice and causing them to partially at least follow the curved lip surface of the outer .nozzle -to travel in spray form4 laterally from the nozzleaxis.

6. In a spray head of the lclass described, outer and inner nozzles with a space therebetween, said inner nozzle being formed with circumferentialgrooves within said space means for providing a spiral passage in a portion of said space at the rear of said grooves, said outer nozzle hav- 75 aosasoa ing provision for the on of air under pressure at the rear of said means, and said in. ner nozzle having provision for the admission thereto of a material to be sprayed and tor the discharge of the material into said space forwardly of said means and at the rear of said circumferential grooves.

"I. In a spray headof the class described; outer and inner nozzles with a space therebetween, batfle means in said space, means for providing a spiral passage in a portion of said space at the rear o! said bame means, said outer nozzle having provision for the n of air under pressure attherearofsaldspiralmeanaandsaidinner nozzle having provision for the admission theref to at the rear thereof of a material to be sprayed and provision between said means for the lateral discharge of material-into said space in the path of movement of air discharged throum said spiral means. 

